Ultrathin optical panel and a method of making an ultrathin optical panel

ABSTRACT

An ultrathin optical panel, and a method of producing an ultrathin optical panel, are disclosed, including stacking a plurality of glass sheets, which sheets may be coated With a transparent cladding substance or may be uncoated, fastening together the plurality of stacked coated glass sheets using an epoxy or ultraviolet adhesive, applying uniform pressure to the stack, curing the stack, sawing the stack to form an inlet face on a side of the stack and an outlet face on an opposed side of the stack, bonding a coupler to the inlet face of the stack, and fastening the stack, having the coupler bonded thereto, within a rectangular housing having an open front which is aligned with the outlet face, the rectangular housing having therein a light generator which is optically aligned with the coupler. The light generator is preferably placed parallel to and proximate with the inlet face, thereby allowing for a reduction in the depth of the housing.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a divisional of U.S. patent application Ser. No.09/318,934, filed May 26, 1999, now U.S. Pat. No. 6,301,417, andentitled “ULTRATHIN OPTICAL PANEL AND A METHOD OF MAKING AN ULTRATHINOPTICAL PANEL”, which is a continuation-in-part of U.S. patentapplication Ser. No. 09/145,411, filed Aug. 31, 1998, and entitled“ULTRATHIN DISPLAY PANEL”, now abandoned.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

This invention was made with federal government support under contractnumber DE-AC02-98CH10886, awarded by the U.S. Department of Energy. Thegovernment has certain rights in the invention.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to planar optical displays, and, moreparticularly, to an ultrathin display panel and a method of making anultrathin display panel.

2. Description of the Background

Optical screens typically use cathode ray tubes (CRTs) for projectingimages onto the screen. The standard screen has a width to height ratioof 4:3 with 525 vertical lines of resolution. An electron beam isscanned both horizontally and vertically across the screen to form anumber of pixels which collectively form the image.

Conventional cathode ray tubes have a practical limit in size, and arerelatively deep to accommodate the required electron gun. Larger screensare available which typically include various forms of image projection.However, such screens have various viewing shortcomings includinglimited viewing angle, resolution, brightness, and contrast, and suchscreens are typically relatively cumbersome in weight and shape.Furthermore, it is desirable for screens of any size to appear black inorder to improve viewing contrast. However, it is impossible for directview CRTs to actually be black because they utilize phosphors to formimages, and those phosphors are non-black.

Optical panels may be made by stacking waveguides defining a wedge andhaving a narrow inlet face along the bottom of the wedge and a verticaloutlet screen disposed obliquely to the inlet face. Such a panel may bethin in its depth compared to its height and width, and the cladding ofthe waveguides may be made black to increase the black surface area, butsuch a panel may require expensive and cumbersome projection equipmentto distribute the image light across the narrow inlet face, whichequipment thereby increases the total size of the panel.

Therefore, the need exists for an optical panel which possesses theadvantages corresponding to a stacked waveguide panel, but which doesnot require the use of expensive and cumbersome projection equipment,nor suffer from the increase in size necessitated by such equipment.

SUMMARY OF THE INVENTION

The present invention is directed to an ultrathin optical panel. Thepanel includes a plurality of stacked optical waveguides ,wherein theplurality forms an outlet face and an inlet face, and at least onecoupler connected to the inlet face which redirects light along anon-perpendicular axis to the inlet face to a perpendicular axis to theinlet face. The coupler allows the panel to be created using simplelight generating equipment, and allows that equipment to be mounted inclose proximity with the inlet face.

The present invention is also directed to a method of producing anultrathin optical panel. The method includes vertically stacking aplurality of glass sheets, which sheets may be coated with a transparentcladding substance or may be uncoated, fastening together the pluralityof stacked coated glass sheets using an epoxy or ultraviolet adhesive,applying uniform pressure to the stack, curing the stack, sawing thestack to form an inlet face on a side of the stack and an outlet face onan opposed side of the stack, bonding a coupler to the inlet face of thestack, and fastening the stack, having the coupler bonded thereto,within a rectangular housing having an open front which is aligned withthe outlet face, the rectangular housing having therein a lightgenerator which is optically aligned with the coupler.

The present invention solves problems experienced in the prior art, suchas the required use of expensive and cumbersome projection equipment, byproviding a light inlet which, though smaller in surface area than theoutlet face, is large enough and symmetrical enough to not necessitatethe use of expensive projection equipment. The present invention alsoretains the advantages which correspond to a stacked waveguide panel,such as improved contrast and minimized depth.

Those and other advantages and benefits of the present invention willbecome apparent from the detailed description of the inventionhereinbelow.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

For the present invention to be clearly understood and readilypracticed, the present invention will be described in conjunction withthe following figures, wherein:

FIG. 1 is an isometric view schematic illustrating an optical panel;

FIG. 2 is a side view cross sectional schematic of an ultrathin opticalpanel; and

FIG. 3 is a schematic illustrating a horizontal and vertical crosssection of an ultrathin display panel using a prismatic coupler.

DETAILED DESCRIPTION OF THE INVENTION

It is to be understood that the figures and descriptions of the presentinvention have been simplified to illustrate elements that are relevantfor a clear understanding of the present invention, while eliminating,for purposes of clarity, many other elements found in a typical opticaldisplay panel. Those of ordinary skill in the art will recognize thatother elements are desirable and/or required in order to implement thepresent invention. However, because such elements are well known in theart, and because they do not facilitate a better understanding of thepresent invention, a discussion of such elements is not provided herein.

FIG. 1 is an isometric view schematic illustrating an optical panel 10.The optical panel 10 includes a plurality of waveguides 10 a, whereinone end of each waveguide 10 a forms an inlet for that waveguide, andwherein the opposite end of each waveguide 10 a forms an outlet for thatwaveguide 10 a, a light generation system 12, a housing 14 in which thelight generation system 12 and the plurality of waveguides 10 a aremounted, and a coupler 16.

Each waveguide 10 a extends horizontally, and the plurality of stackedwaveguides 10 a extends vertically. The plurality of inlet ends definean inlet face 20 for receiving image light 22. The plurality of outletends define an outlet face 24 disposed substantially parallel with theinlet face 20 for displaying light 22. The light 22 may be displayed ina form such as, but not limited to, a video image 22 a.

The housing 14 is sized larger in height and width than the combinationof the light generation system 12 and the plurality of waveguides 10 a,to allow the placement of the plurality 10 a and light generation system12 therein. The housing 14 has an open front to allow for viewing of theoutlet face 24, and has a closed depth D looking from the open front tothe back of the housing 14.

The light generation system 12 provides the light viewed through thewaveguides 10 a. The light generation system 12 includes a light source30, and a light redirection element 32 that redirects incident light 22from the light source 30 into the coupler 16, which light redirectionelement 32, in combination with the coupler 16, allows for a reductionin the depth D of the housing 14. This reduction allowance occurs wherethe light redirection element 32 is configured for turning the light 22from a source 30, which source 30 is placed within the housing 14proximate to and parallel with the vertical stack of the plurality ofwaveguides 10 a, into the coupler 16, which then acutely turns the light22 into the waveguides 10 a. The coupler 16 is preferably effective forturning the image light in an exemplary range of about 45° up to about90°, in order to generate approximately horizontal transmission throughthe plurality of waveguides 10 a. The light generation system 12 mayalso include a modulator and further imaging optics. The lightgeneration system 12 is discussed with more particularity with respectto FIG. 2.

The parallel surfaces of the inlet face 20 and the outlet face 24 allowthe panel 10 and enclosing housing 14 to be made ultrathin in depth. Thepanel 10 has a nominal thickness T which is the depth of the waveguides10 a between the inlet face 20 and the outlet face 24, and thickness Tis substantially less than the height H and width W of the outlet face24. The panel 10 may be configured in typical television width to heightratios of 4:3 or 16:9, for example. For a height H of about 100 cm and awidth W of about 133 cm, the panel thickness T of the present inventionmay be about 1 cm. The depth D may vary accordingly with the thicknessT, but, in the embodiment described hereinabove, the depth D of thehousing 14 is preferably no greater than about 12 cm.

FIG. 2 is a side view cross sectional schematic of an ultrathin opticalpanel 10. The panel 10 includes a plurality of stacked waveguides 10 a,a light generation system 12, a coupler 16, and a housing 14.

The light generation system 12, in one embodiment of the presentinvention, includes a projector 60 which is optically aligned with alight redirection element 32. An image is projected onto the lightredirection element 32, and is then redirected to the coupler 16 fortransmission through the waveguides 10 a for display on the outlet face24. In a preferred embodiment, the projector 60 is disposed adjacent tothe top of the inlet face 20 for projecting the image light 22 generallyparallel thereto, and is spaced therefrom a distance sufficient to allowfor a turning of the image light 22 from the light redirection element32 into the coupler 16 for transmission through the waveguides 10 a.

The projector 60 may include a suitable light source 30 for producingthe light 22. The light source 30 may be a light bulb, slide projector,video projector, or laser, for example. The projector 60 may alsoinclude a modulator 62 for modulating the light 22 to form an image 22a. The modulator 62 may be, for example, a conventional Liquid CrystalDisplay (LCD), a Digital Micromirror Device (DMD), a GLV, a laser rasterscanner, a PDLC, an LCOS, a MEMS, or a CRT. The projector 60 may alsoinclude suitable image optics 64 for distributing or broadcasting theimage light 22 horizontally and vertically across the light redirectionelement 32 for properly focused transmission to the coupler 16. Theimage optics 64 may include focusing and expanding lenses and mirrors.One or more light generation systems 12, such as between 2 and 4 suchsystems, may be used to provide light to one or more portions of thecoupler 16. Expansion lenses may be used for both the imaging optics 64and the light redirection element 32 to expand the image light 22 bothvertically and horizontally over the coupler 16. Alternatively, suitablerastering systems may be used as the light generation system 12 to formthe image by rastering the image light 22 both horizontally andvertically across the coupler 16.

In the illustrated embodiment, the light 22 is initially projected fromthe projector 60 vertically downward inside the housing 14 to the bottomthereof where the light redirection elements 32 are mounted, and thelight redirection elements 32 then redirect the image light 22vertically upwardly at a small acute angle for broadcast over the entireexposed surface of the coupler 16. In an alternative embodiment, theprojector 60 could be placed beneath the inlet face 20 rather thanbehind the inlet face 20.

The allowable incidence angle of the image light 22 on the coupler 16 isdetermined by the capability of the coupler 16 to turn the light 22 intothe inlet face 20 of the panel 10. The greater the turning capability ofthe coupler 16, the closer the projector 60 may be mounted to thecoupler 60 for reducing the required depth D of the housing 14.

FIG. 3 is a schematic illustrating a horizontal and vertical crosssection of an ultrathin optical panel 10. The panel 10 includes aplurality of vertically stacked optical waveguides 10 a, a lightgeneration system 12 (see FIG. 2), a coupler 16, and a housing 14.

Each waveguide 10 a of the plurality of waveguides 10 a includes acentral transparent core 80 having a first index of refraction. The core80 may be formed of any material known in the art to be suitable forpassing electromagnetic waves therethrough, such as, but not limited toplexiglass or polymers. The central core 80 may be formed of an opticalplastic, such as Lexan®, commercially available from the GeneralElectric Company®, or glass, such as type BK7. The preferred embodimentof the present invention is implemented using individual glass sheets,which are typically in the range between 2 and 40 microns thick, andwhich may be of a manageable length and width. The central core 80 islaminated between at least two cladding layers 82. The cladding layers82 immediately in contact with the glass have a second index ofrefraction lower than that of the cores 80, thus allowing forsubstantially total internal reflection of the light 22 as it istransmitted through the cores 80. The cladding 82 may be a suitableplastic, glass, plastic, polyurethane, low refractive index polymer, orepoxy, for example, and is preferably black in color. Where multiplecladding layers 82 are used, it is preferable that a clear claddinglayer contact the glass, and a black cladding layer be disposed betweenadjacent clear cladding layers, thus improving both viewing contrast ofthe outlet face 24 and internal reflection of the light 22 through thecore 80. The use of at least one black cladding layer 82 providesimproved contrast by providing additional blackness at the outlet face24. Further, the exposed edges of the black cladding 82 at the outletface 24 are directly viewable to the observer. Additionally, ambientlight which enters the waveguides off-axis through the outlet face 24will be absorbed internally by the black cladding 82. The black cladding82 may be formed in any suitable manner such as with black spray paint,or carbon particles within an epoxy adhesive joining together theadjacent cores 80 in one or more black cladding layers 82. The manner offorming the cladding layers 82 and cores 80 is discussed with morespecificity hereinbelow.

The waveguides 10 a of the preferred embodiment are in the form of flatribbons extending continuously in the horizontal direction along thewidth of the outlet face 24. The ribbon waveguides 10 a are preferablystacked vertically along the height of the outlet face 24. The verticalresolution of the panel 10 is thus dependent on the number of waveguides10 a stacked along the height of the outlet face 24. For example, astacking of 525 waveguides would provide 525 vertical lines ofresolution.

The plurality of stacked waveguides 10 a may be formed by first laying afirst glass sheet in a trough sized slightly larger than the first glasssheet. The trough may then be filled with a thermally curing epoxy. Theepoxy is preferably black, in order to form a black layer betweenwaveguides, thereby providing improved viewing contrast. Furthermore,the epoxy should possess the properties of a suitable cladding layer 82,such as having a lower index of refraction than the glass sheets toallow substantially total internal reflection of the light 22 within theglass sheet. After filling of the trough, glass sheets 80 are repeatedlystacked, and a layer of epoxy forms between each glass sheet 80. Thestacking is preferably repeated until between approximately 500 and 800sheets have been stacked. Uniform pressure may then be applied to thestack, thereby causing the epoxy to flow to a generally uniform levelbetween glass sheets 80. In a preferred embodiment of the presentinvention, the uniform level obtained is approximately 0.0002″ betweenglass sheets 80. The stack may then be baked to cure at 80 degreesCelsius for such time as is necessary to cure the epoxy, and the stackis then allowed to cool slowly in order to prevent cracking of theglass. After curing, the stack may be placed against a saw, such as, butnot limited to, a diamond saw, and cut to a desired size. The cutportions of the panel 10 may then be polished with a diamond polisher toremove any saw marks.

In an alternative embodiment of the present invention, a plurality ofglass sheets 80 are individually coated with, or dipped within, asubstance having an index of refraction lower than that of the glass,and the plurality of coated sheets are fastened together using glue orthermally curing epoxy, which is preferably black in color. A firstcoated glass sheet 10 a is placed in a trough sized slightly larger thanthe first coated glass sheet 10 a, the trough is filled with a thermallycuring black epoxy, and the coated glass sheets 10 a are repeatedlystacked, forming a layer of epoxy between each coated glass sheet 10 a.The stacking is preferably repeated until between approximately 500 and800 sheets have been stacked. Uniform pressure may then be applied tothe stack, followed by a cure of the epoxy, and a sawing of the stackinto a desired size. The stack may be sawed curved or flat, and may befrosted or polished after sawing.

In another alternative embodiment of the present invention, the glasssheets 80 preferably have a width in the range between 0.5″ and 1.0″,and are of a manageable length, such as between 12″ and 36″. The sheets80 are stacked, with a layer of black ultraviolet adhesive being placedbetween each sheet 80. Ultraviolet radiation is then used to cure eachadhesive layer, and the stack may then be cut and/or polished.

After sawing and/or polishing the stack, each of the above embodimentsof the method also includes bonding a coupler 16 to the inlet face 20 ofthe stack, and fastening the stack, having the coupler 16 bondedthereto, within the rectangular housing 14. The stack is fastened suchthat the open front of the housing 14 is aligned with the outlet face24, and the light generator 12 within the housing 14 is opticallyaligned with the coupler 16.

The light generation system 12 provides light 22 which is incident onthe coupler 16, and is substantially as discussed with respect to FIG.2. The source 30 of the light generation system 12 may be mounted withinthe housing 14 in a suitable location to minimize the volume and depthof the housing 14. The source 30 is preferably mounted within thehousing 14 directly behind the inlet face 20 at the top thereof toinitially project light 22 vertically downwardly, which light is 22 thenturned by elements 32 of the light generation system 12 verticallyupwardly to optically engage the coupler 16. In the preferred embodimentof the present invention, the individual waveguides 10 a extendhorizontally without inclination, thus allowing the image to betransmitted directly horizontally through the waveguides 10 a for directviewing by an observer, thereby allowing the viewer to receive fullintensity of the light 22 for maximum brightness. Thus, for maximumbrightness, the light 22 incident from the light generation system 12must be turned substantially horizontally. A prismatic coupler 16 may beused to turn the light at an angle up to 90 degrees for entry into theinlet face 20. In one embodiment of the present invention, a TRAF turnsthe light at an angle of 81 degrees.

The light coupler 16 adjoins the entire inlet face 20 and may besuitably bonded thereto for coupling or redirecting the light 22incident from the light generation system 12 into the inlet face 20 fortransmission through the waveguides 10 a. The waveguides 10 a of thepresent invention may have a limited acceptance angle for receivingincident light 22, and the coupler 16 is aligned to ensure that theimage light 22 is suitably turned to enter the waveguide cores 80 withinthe allowable acceptance angle.

In a preferred embodiment of the present invention discussedhereinabove, the coupler 16 includes fresnel prismatic grooves 16 a thatare straight along the width of the inlet face 20 and are spacedvertically apart along the height of the inlet face 20, which prismaticcoupler 16 is capable of turning light up to an angle of 90 degrees. Ina preferred embodiment of the present invention, the prismatic coupler16 is a Transmissive Right Angle Film (TRAF) commercially available fromthe 3M Company® of St. Paul, Minn. under the tradename TRAF II®. Anoptional reflector may be disposed closely adjacent to the prismaticcoupler 16 for reflecting back into the waveguides 10 a any stray light22 at the grooves 16 a.

The coupler 16 may also take the form of a diffractive element 16. Thediffractive coupler 16 includes a diffractive grating having a largenumber of small grooves extending horizontally and parallel with theindividual waveguides 10 a, which grooves are closely spaced together inthe vertical direction over the height of the inlet face 20. The coupler16 may take other forms as well, including, but not limited to,holographic elements.

The housing 14 supports the waveguide stack 10 a and the lightgeneration system 12 in a substantially closed enclosure. The outletface 24 faces outwardly and is exposed to the viewer and ambient light,and the inlet face 20 and adjoining coupler 16 face inwardly toward thepreferably black surfaces within the housing 14, thereby providingadditional black for contrast at the outlet face 24. This additionalblack is provided at the outlet face 24 due to the passive nature of thewaveguides 10 a and the coupler 16. When these passive devices areenclosed in a black area, the outlet face 24 will appear black when notilluminated by image light 22 incident on the inlet face 20.

Those of ordinary skill in the art will recognize that manymodifications and variations of the present invention may beimplemented. The foregoing description and the following claims areintended to cover all such modifications and variations.

What is claimed is:
 1. A method of producing an optical panel for displaying a projected light image, comprising: laying a first planar sheet in a trough sized slightly larger than the first sheet; filling the trough with a thermally curing epoxy; stacking additional planar sheets atop the first planar sheet, thereby forming a layer of epoxy between each planar sheet; applying uniform pressure to the stack, thereby causing the epoxy to flow to a generally uniform level between planar sheets; baking the stack to cure; cooling the stack; sawing the stack to form an inlet face on a side of the stack and an outlet face on an opposed side of the stack such that the inlet face is substantially parallel to the outlet face; bonding a coupler to the inlet face of the stack, wherein the coupler redirects light that forms the projected light image along a non-perpendicular axis to the inlet face to a perpendicular axis to the inlet face; and fastening the stack, having the coupler bonded thereto, within a rectangular housing having an open front which is aligned with the outlet face, the rectangular housing having therein a light generator which is optically aligned with the coupler.
 2. The method of claim 1, wherein the epoxy is black in color.
 3. The method of claim 1, wherein the epoxy has a lower index of refraction than the planar sheets.
 4. The method of claim 1, wherein said stacking is repeated until between about 500 and about 800 planar sheets have been stacked.
 5. The method of claim 1, wherein the generally uniform level of epoxy is about 0.0002″ in depth between planar sheets.
 6. The method of claim 1, wherein said baking is at about 80 degrees Celsius.
 7. The method of claim 1, wherein said sawing is performed using a diamond saw.
 8. The method of claim 1, further comprising polishing the stack with a diamond polisher after said sawing.
 9. The method of claim 1, further comprising frosting the outlet face after said sawing.
 10. A method of producing an optical panel for displaying a projected light image, comprising: individually coating a plurality of planar sheets with a clear cladding material having an index of refraction lower than that of the planar sheets; vertically stacking a plurality of coated planar sheets; fastening together the plurality of stacked coated planar sheets using an epoxy; applying uniform pressure to the stack; baking the stack to cure; sawing the stack to form an inlet face on a side of the stack and an outlet face on an opposed side of the stack such that the inlet face is substantially parallel to the outlet face; bonding a coupler to the inlet face of the stack, wherein the coupler redirects light that forms the projected light image along a non-perpendicular axis to the inlet face to a perpendicular axis to the inlet face; and fastening the stack, having the coupler bonded thereto, within a rectangular housing having an open front which is aligned with the outlet face, the rectangular housing having therein a light generator which is optically aligned with the coupler.
 11. The method of claim 10, wherein the epoxy is black in color.
 12. The method of claim 10, wherein said vertical stacking is performed in a trough sized slightly larger than the surface area of one coated planar sheet.
 13. The method of claim 12, wherein said fastening comprises filling the trough with a thermally curing black epoxy before stacking.
 14. The method of claim 10, wherein said vertical stacking is repeated until between about 500 and about 800 planar sheets have been stacked.
 15. The method of claim 10, further comprising frosting the inlet face and the outlet face after said sawing.
 16. The method of claim 10, further comprising polishing the inlet face and the outlet face with a diamond polisher after said sawing.
 17. A method of producing an optical panel for displaying a projected light image, comprising: stacking a plurality of planar sheets, each planar sheet having a width in the range between about 0.5″ and about 1.0″, and a length in the range between about 12″ and 36″; placing a layer of black ultraviolet adhesive between each planar sheet in the stack; curing each layer of the black ultraviolet adhesive using ultraviolet radiation; sawing the stack to form an inlet face on a side of the stack and an outlet face on an opposed side of the stack such that the inlet face is substantially parallel to the outlet face; bonding a coupler to the inlet face of the stack, wherein the coupler redirects light that forms the projected light image along a non-perpendicular axis to the inlet face to a perpendicular axis to the inlet face; and fastening the stack, having the coupler bonded thereto, within a rectangular housing having an open front which is aligned with the outlet face, the rectangular housing having therein a light generator which is optically aligned with the coupler.
 18. The method of claim 17, wherein said stacking is repeated until between about 500 and about 800 planar sheets have been stacked.
 19. The method of claim 17, further comprising frosting the inlet face and the outlet face after said sawing.
 20. The method of claim 17, further comprising polishing the inlet face and the outlet face with a diamond polisher after said sawing.
 21. A method of producing an optical panel for displaying a projected image, comprising: laying a first planar sheet in a trough sized slightly larger than the first sheet; filling the trough with a thermally curing epoxy; stacking additional planar sheets atop the first planar sheet, thereby forming a layer of epoxy between each planar sheet; applying uniform pressure to the stack, thereby causing the epoxy to flow to a generally uniform level between planar sheets; baking the stack to cure; cooling the stack; sawing the stack to form an inlet face on a side of the stack and an outlet face on an opposed side of the stack such that the inlet face is substantially parallel to the outlet face; bonding a coupler to the inlet face of the stack, wherein the coupler redirects light along a non-perpendicular axis to the inlet face to a perpendicular axis to the inlet face, and wherein the light forms an image which is projected through the optical panel and is formed at the outlet face; and fastening the stack, having the coupler bonded thereto, within a rectangular housing having an open front which is aligned with the outlet face, the rectangular housing having therein a light generator which is optically aligned with the coupler.
 22. The method of claim 21, wherein the epoxy is black in color.
 23. The method of claim 21, wherein the epoxy has a lower index of refraction than the planar sheets.
 24. The method of claim 21, wherein said stacking is repeated until between about 500 and about 800 planar sheets have been stacked.
 25. The method of claim 21, wherein the generally uniform level of epoxy is about 0.0002″ in depth between planar sheets.
 26. The method of claim 21, wherein said baking is at about 80 degrees Celsius.
 27. The method of claim 21, wherein said sawing is performed using a diamond saw.
 28. The method of claim 21, further comprising polishing the stack with a diamond polisher after said sawing.
 29. The method of claim 21, further comprising frosting the outlet face after said sawing.
 30. A method of producing an optical panel for displaying a projected image, comprising: individually coating a plurality of planar sheets with a clear cladding material having an index of refraction lower than that of the planar sheets; vertically stacking a plurality of coated planar sheets; fastening together the plurality of stacked coated planar sheets using an epoxy; applying uniform pressure to the stack; baking the stack to cure; sawing the stack to form an inlet face on a side of the stack and an outlet face on an opposed side of the stack such that the inlet face is substantially parallel to the outlet face; bonding a coupler to the inlet face of the stack, wherein the coupler redirects light along a non-perpendicular axis to the inlet face to a perpendicular axis to the inlet face, and wherein the light forms an image which is projected through the optical panel and is formed at the outlet face; and fastening the stack, having the coupler bonded thereto, within a rectangular housing having an open front which is aligned with the outlet face, the rectangular housing having therein a light generator which is optically aligned with the coupler.
 31. The method of claim 30, wherein the epoxy is black in color.
 32. The method of claim 30, wherein said vertical stacking is performed in a trough sized slightly larger than the surface area of one coated planar sheet.
 33. The method of claim 32, wherein said fastening comprises filling the trough with a thermally curing black epoxy before stacking.
 34. The method of claim 30, wherein said vertical stacking is repeated until between about 500 and about 800 planar sheets have been stacked.
 35. The method of claim 30, further comprising frosting the inlet face and the outlet face after said sawing.
 36. The method of claim 30, further comprising polishing the inlet face and the outlet face with a diamond polisher after said sawing.
 37. A method of producing an optical panel for displaying a projected image, comprising: stacking a plurality of planar sheets, each planar sheet having a width in the range between about 0.5″ and about 1.0″, and a length in the range between about 12″ and 36″; placing a layer of black ultraviolet adhesive between each planar sheet in the stack; curing each layer of the black ultraviolet adhesive using ultraviolet radiation; sawing the stack to form an inlet face on a side of the stack and an outlet face on an opposed side of the stack such that the inlet face is substantially parallel to the outlet face; bonding a coupler to the inlet face of the stack, wherein the coupler redirects light along a non-perpendicular axis to the inlet face to a perpendicular axis to the inlet face, and wherein the light forms an image which is projected through the optical panel and is formed at the outlet face; and fastening the stack, having the coupler bonded thereto, within a rectangular housing having an open front which is aligned with the outlet face, the rectangular housing having therein a light generator which is optically aligned with the coupler.
 38. The method of claim 37, wherein said stacking is repeated until between about 500 and about 800 planar sheets have been stacked.
 39. The method of claim 37, further comprising frosting the inlet face and the outlet face after said sawing.
 40. The method of claim 37, further comprising polishing the inlet face and the outlet face with a diamond polisher after said sawing. 